The present invention relates to space and communications satellites, and more particularly, to a digital signal processing circuit for transmitting and receiving satellite communications.
There is a continually increasing demand for mobile satellite communications by users on the road, on the sea, and in the air. In order to continually expand mobile satellite service to broader markets, low cost mobile systems must be employed.
Current satellite technology directed towards the consumer market typically requires a tracking ground terminal. However, the tracking antennas with this current technology are expensive and bulky and, therefore, generally unacceptable to consumers.
These current conventional tracking ground terminals, include tracking arrays with mechanisms for steering beams, such as phase shifters and/or gimbals. These tracking arrays further include integrated mechanisms for tracking the pointing directions of beams, such as monopulse tracking loops, step scan, and open loop pointing schemes. These conventional tracking phased arrays are too expensive for a consumer market, primarily because each phased array has a separate set of electronics associated with each element to process the various signals, including many phase shifters and many duplicate strings of electronics. Therefore, the manufacturing costs for these conventional tracking phased arrays are generally beyond that practical for the consumer market whether for use as a fixed antenna or by a user as a mobile antenna.
It would therefore be desirable to reduce the complexity of the electronic circuitry associated with the mobile terminal and improve the signal processing.
It is an object of the present invention to provide a low profile mobile antenna terminal that employs signal processing circuitry that is reliable, cost effective and reduces the processing load.
In one aspect of the invention, modular mobile terminal for a satellite system is disclosed in which the satellite system has a ground station and a network such as a telephone network coupled to the ground station. Each of the mobile terminals has a radome layer and a support layer having a plurality of circuit traces formed thereon. An element module is coupled between the support layer and the radome layer. Each element module comprises a housing and a radiating patch having a feed therethrough. A dielectric layer is coupled adjacent to the radiating patch. A ground plane is disposed adjacent to the dielectric layer on the opposite side of the dielectric layer as the radiating patch. A plurality of circuit chips is coupled to the ground plane. The support layer of the array has a plurality of circuit traces formed thereon. A plurality of interconnections between the circuit chips and the plurality of traces connect the traces and the circuit chips.
One advantage of the invention is that digital processing circuitry may be incorporated into the array to allow automatic direction tracking which is suitable for the mobile applications. Another aspect of the invention is that the size and complexity compared to a tracking terminal is reduced.
Other objects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.